RUNX1 EXPRESSION IN CUTANEOUS, ORAL, AND NASAL MELANOMAS: A COMPARATIVE IMMUNOHISTOCHEMICAL STUDY

Objective: Previous studies have described that KIT mutations are associated with Runt-related transcription factor 1 (RUNX1) upregulation. As mucosal melanomas show high prevalence of KIT mutations, we propose a study to compare the expression of RUNX1 in cutaneous and mucosal melanomas. Study design: Immunohistochemical RUNX1 expression was evaluated in 67 cutaneous (CM), 25 oral (OM), and 21 nasal melanomas (NM). In addition, we also studied 40 cutaneous and 12 oral nevi. The number of positive nuclei was quantified by a digital computer-assisted method. Results: The index of nuclear RUNX1-positivity was about 23.1%, 67.1%, and 88.2% of tumor cells for CM, OM, and NM, respectively. These indexes were statically significant (P